1. Field of the Invention
Applicant's invention relates to precast barrier systems and a method of construction. More specifically, the present invention relates to a precast concrete column and panel wall having a series of slanted deflection surfaces and a method of constructing such a wall on a foundation surface.
2. Background Information
In recent years, many civil engineering construction projects have used concrete barriers in numerous different applications; such as a retaining wall or as a barrier to keep out intruding people, animals, vehicles, fire, wind, light, sound, heat, and the like. For a concrete barrier to be selected for these different applications, the overall cost of the barrier must be low when considering the manufacturing costs, the manpower costs in construction and the time required to construct the wall. The barrier must also be durable and maintenance free with the possibility of a wide variety of aesthetically pleasing surface finishes. Cast-in-place concrete has given way to the use of precast concrete barriers. Precast concrete barriers are preferred because they can be manufactured at a lower cost with a higher degree of uniformity not found in cast-in-place concrete barriers. The precast concrete barriers may also be erected in numerous configurations and are capable of self support without massive construction.
Another cost which must be considered in many municipal areas is the availability and cost of purchasing right-of-ways for the construction projects. Consideration of the right-of-way requirements is particularly important in highway construction near residential areas. If the roadway is constructed near the residences, then the noise from passing vehicles and the impact of the noise on the nearby residences must be considered. Ideally the highway would be built far enough away from the residences so that the noise would not bother the residences. However, due to the continued growth of urban sprawl and the need for more highways many times there just is not enough land available. In these situations, sound abatement walls are constructed to minimize the noise reaching the residence. Unfortunately, many of the current barrier designs require more right-of-way land than that which is available.
The need to reduce right-of-way requirements and the need to reduce costs has created a need for an environmental barrier system in which the width of barrier construction is small and which may be straight, curved, angled, or which may follow a terrain of any contour. The straighter and narrower the barrier construction, the lower overall construction costs since less land must be acquired.
Current free standing barrier designs typically use an undulating pattern to achieve the free standing structure. The barrier may use either a zigzag or other offset arrangement of panels that is self supporting. One offset type of barrier system is illustrated and described in U.S. Pat. No. 4,111,401, which was issued on Sep. 5, 1978 to William H. Pickett. An example of a structure having zigzag type of barrier system is illustrated and described in U.S. Pat. No. 3,732,653, which issued on May 15, 1973 to William H. Pickett. One problem with both of these designs is that they require a large amount of right-of-way land to allow room for the large width of barrier construction necessary for the barrier to be self supporting.
When freestanding undulating barriers are converted to straight line applications, column and panel arrangements have generally been found to be preferable to other barrier designs such as embedding panels. In a column and panel arrangement, a plurality of columns are spaced at predetermined distances from one another along the desired line for the barrier. When the columns are set in position, panels made of metal, concrete, wood, plastic or the like are supported between adjacent columns to create the barrier structure.
Current column and panel barriers experience a variety of problems. One problem associated with these column and panel barriers is the need to very precisely position adjacent columns if prefabricated panels are to be positioned in between. The positioning problem includes not only the column-to-column spacing but also the plumbness of the column both to the wall face and the panel edge. Once the panel dimensions are selected and the panels are fabricated, then the spacing between adjacent columns must correspond to the panel length for the full exposed length of the column. If precise column positioning is not maintained, then the panels will not fit between columns which are spaced too close or the panels cannot be attached to columns which are spaced too far apart.
In typical precast concrete construction, tolerances of plus or minus 1/4 inch or more are common depending upon the fabricators' experience and the cost of forms. Accumulation of such tolerances require that positioning and placement of columns be very precise in order to accommodate the precast panels therebetween. Precise tolerances on the lateral spacing between columns can be very difficult to maintain at construction sites. Consequently, accumulation of tolerances can lead to a loose joint between panels and columns. With a loose joint, vibration can occur and sound, light, and other forces or energy can pass through the barrier. The present invention overcomes the problems with precise tolerances without any significant additional costs.
Another problem associated with column and panel barriers concerns thermally induced linear expansion and contraction of the completed barrier. Thermal variations in the wall can lead to loose joints during contraction as discussed above, structural damage of the columns and panels due to compressive stress developed during expansion, and construction difficulty when large thermal variations occur during construction. Thus, there is a need for a precast concrete barrier which overcomes problems of the types discussed above for column and panel barriers.